Suasively

adv. [f. prec. + -LY².] In a suasive manner; so as to persuade.

1837.  Carlyle, Fr. Rev., I. III. ii. Let a true tale, of his Majesty’s … wretched pecuniary impossibilities, be suasively told them.

1871.  T. Hardy, Desperate Remedies, II. 134. ‘You must remember,’ she added, more suasively, ‘that Miss Graye has a perfect right to do what she likes with her own—her heart, that is to say.’

  So Suasiveness.

1727.  Bailey, vol. II.

1885.  Homilet. Rev., June, 481. The leading examples of the early style [of preaching] … characterized by much unction and suasiveness.